The glow from Olympic victory is notoriously short-lived. Prudent, then, that champion swimmer Michael Phelps is moving quickly to convert his Olympic buzz into sweet endorsement cash. Over the next week, Phelps will promote his existing sponsors. Then he's off to London and, several days later, New York, reports theWall Street Journal. The athlete is estimated worth upwards of $40 million to Nike alone, assuming he switches to their swimwear from Speedo, and his agent estimates he can take in $100 million over the course of his lifetime. That aggressive number still values each of Phelps' 14 gold medals (eight this Olympiad alone) well below the going rate for top celebrity babies. And reaching the payday has been infinitely harder for Phelps, not to mention more tricky. Look at all the sometimes wacky and ill-considered endorsement possibilities he'll have to carefully navigate, lest he tarnish his brand:

Electronics (Phelps partnered with a Hong Kong-based MP3 player after the Athens games in 2004)

Even if Phelps makes his agent's estimate of $100 million, he will stake make in a lifetime what golfer Tiger Woods makes in a year, since Woods is constantly playing and, presumably, picked a sport of greater interest to the wealthy.

But Woods' groupies probably aren't half as hot or a tenth as numerous.